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Radiocarbon dating. Samples of carbon dioxide being loaded into a linear accelerator (linac) for radiocarbon dating. This analyses the amount of carbon-14 (14C) in the gas, produced by the combustion of the sample in oxygen. The linac is used as the mass of 14C is so close to that of nitrogen-14 from the sample. The ratio of radioactive 14C to stable carbon-12 may be related to the time since the death of the animal or plant being investigated. Convention states that 14C has a half-life of 5568 years (+/- 30 years), but this is now thought to be too short. Dates are given either as radiocarbon dates, or solar dates after corrections are made.